Nelly's sister Jacqueline Donahue, 31, lost her three-year battle with leukemia Thursday morning.

In 2003, Donahue co-founded the Jes Us 4 Jackie Foundation, dedicated to educating black people about bone-marrow and stem-cell transplants. Nelly also worked to raise awareness of his sister's disease, and has appeared at numerous events to enroll minority participants in the National Bone Marrow Registry (see [article id="1473175"]"Nelly Encourages Minorities To Become Bone-Marrow Donors"[/article]). Bone-marrow transplants can often offer a better chance of survival for those suffering from leukemia.

A statement from Nelly's family and the Jes Us 4 Jackie Foundation said, "We want to thank everyone for their love and support of Jackie. In particular, we want to thank those who participated in the Jes Us 4 Jackie bone-marrow drives. We are very proud of her efforts to educate and raise awareness about the disease and the need for African-Americans to join the National Donor Registry. She will always be remembered for her loving spirit, energy, courage, and unshakeable faith."

After performing at the Star of Texas Rodeo in Austin, Texas, Wednesday night, Nelly canceled Thursday night's (March 24) performance in Beaumont, Texas, as well as shows he had planned for Friday, Saturday and Monday. It has not yet been determined when he'll resume his tour, which also features Fat Joe and T.I.

His label said, "We are saddened by the loss of Nelly's sister, Jackie Donahue, and extend our deepest sympathies and condolences to Nelly and Jackie's family during this difficult time."